Abstract: A light controlling device having excellent controllability of light and solar energy transmission which comprises a suspension of anisotropic particles in an liquid dielectric medium and a pair of electrodes for applying an electric field to said suspension, and said anisotropic particles having an aspect ratio of at least 3.5 and comprising an inorganic titanium compound having an absorption coefficient of at least 5.times.10.sup.3 cm.sup.-1, especially a titanium compound of the formula: TiOxNy wherein 1.37.ltoreq.x.sup.+ y.ltoreq.1.95 and 0.15.ltoreq.y.ltoreq.0.92.

Abstract: A method of producing a water treatment medium comprises the steps of dispersing staple fibers in a dispersive medium liquid, and causing the fibers to flow and vibrate in the liquid so that the fibers are mutually intertwined or entangled to form spherical or spheroidal or discal fiber lumps.This method is adapted for quantity production, and the resulting fiber lumps are of high quality and provide an improved filtration efficiency and effect in comparison with conventional filter media.

Abstract: A filtration apparatus comprising a filter tank, a support provided at least at a lower interior portion of the filter tank, a filter medium layer composed of fiber lumps accumulated on the support, a filter medium spreading zone provided within the filter tank above the support, air injecting means disposed under the filter medium layer, prefilt inlet means disposed at an upper portion of the tank, and filtrate outlet means disposed at a lower portion of the tank. The apparatus is simple in construction and easy to operate, assures depth-type filtration with high accuracy and is easy to wash for the reuse of the filter medium.